I’d like to report a possible bug within Athena.

 

Last week I collected Br K-edge data at the APS and have experienced an issue with Athena during data alignment. The beamline energy required calibration and so I did the following data processing steps, in this order:

 

1.       Completed pre- and post-edge corrections, using windows relative to the actual Br K-edge energy, on the raw data exported from the beamline. (In other words these windows were not energy offsets relative to the actual measured edge position).

2.       Used the flatten post-edge feature within Athena.

3.       ‘Calibrated’ (Normalised is a better term really) the first derivative of a NaBr measurement to the Br K-edge energy using the calibrate drop-down option. This resulted in the requirement for a -17.39 eV energy offset.

4.       Tried to align all of the sample data to the NaBr ‘standard’ using the align drop-down option.

 

The issue I have had is with step #4. When I aligned, for several samples the XAFS (XANES) plots went wrong. It seems that Athena was not transforming the pre- and post-edge windows correctly for such a large energy shift, i.e. didn’t shift these to lower energies by 17.39 eV, and I think this is a bug within Athena.

 

I hope the above makes sense; I can provide an Athena project file, if required.

 

Many thanks, Leon

 

 

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Dr Leon J. Clarke

Senior Lecturer in Environmental Analytical Chemistry

Division of Chemistry and Environmental Sciences

School of Science and the Environment

Faculty of Science and Engineering

Manchester Metropolitan University

John Dalton East

Oxford Road

Manchester

M1 5GD

 

E-mail: l.clarke@mmu.ac.uk

WWW: http://www.sste.mmu.ac.uk/

Tel: +44 (0)161 247 1412